Or do you put on a new set and then disconnect to prime? I always attach the set to the filled resvoir, put it into the pump, prime, attache the new set and then so a fixed prime. But in one of the numerous booklets and paperwork (maybe for the mio?) I saw the directions said to do the site change "dry" and then discommect it and attach to the res as usual and fill the tubing. then when you reattach you do the fixed prime. I guess it doesn't really matter (as long as you are not connected when priming!!!) but it seemed a little odd to me.